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5: Fluctuations

  • Page ID
    34719
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    This chapter discusses fluctuations of macroscopic variables, mostly at thermodynamic equilibrium. In particular, it describes the intimate connection between fluctuations and dissipation (damping) in dynamic systems weakly coupled to multi-particle environments, which culminates in the Einstein relation between the diffusion coefficient and mobility, the Nyquist formula, and its quantum mechanical generalization – the fluctuation-dissipation theorem. An alternative approach to the same problem, based on the Smoluchowski and Fokker-Planck equations, is also discussed in brief.

    Thumbnail: The Kramers problem.


    This page titled 5: Fluctuations is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Konstantin K. Likharev via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.

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